1. Field of the Invention
The present invention relates to a method for manufacturing a silicon carbide semiconductor device, and in particular to a method for manufacturing a silicon carbide semiconductor device including a collector layer having p type.
2. Description of the Background Art
For example, “9 kV 4H—SiC IGBTs with 88 mΩ·cm2 of Rdiff,on” by Qingchun Zhang et al., Mater. Sci. Forum Vols. 556-557 (2007), pp. 771-774 discloses a p channel type IGBT (Insulated Gate Bipolar Transistor) using a 4H—SiC substrate (silicon carbide substrate having a polytype of 4H) having n type. The literature describes that a p channel type IGBT is adopted instead of an n channel type IGBT due to shortage of high-quality, low-resistance p-SiC substrates necessary for the n channel type IGBT.
As described above, it is difficult to prepare a p type SiC substrate for manufacturing an n channel type IGBT, in particular a 4H—SiC substrate suitable for a power semiconductor device, having sufficient properties. This is because bulk growth of p type 4H—SiC is difficult and problems are likely to occur in crystallinity and the like during growth.